Apparatus for dyeing tubular knit material



Aug. 2, 1966 s. COHN ET AL 3,263,458

APPARATUS FOR DYEING TUBULAR KNIT MATERIAL Original Filed Sept. 13. 19605 Sheets-Sheet l INVENTORS SAMUEL COHN EUGENE COHN BY FRANK CATALLOww/wmpzw gab ATTORNEY Aug. 2, 1966 s. COHN ET AL APPARATUS FOR DYEINGTUBULAR KNIT MATERIAL 5 Sheets-Sheet 2 )riginal Filed Sept. 13 1960 o wN SHNU. .ZJQ m wm a TCCA JN N C R U wa am mum K T MGM A AU R SEF L W Y Bw m u i NN ll United States Patent 3,263,458 APPARATUS FQR DYEINGTUBULAR KNIT MATERIAL Samuel Cohn, New York, Eugene (john, Great Neck,and Frank Catallo, Elmont, N.Y., assignors to Samcoe HoldingCorporation, Woodside, N.Y., a corporation of New York Continuation ofapplication Ser. No. 55,672, Sept. 13, 1960. This application Aug. 14,1963. Ser. No. 302,094 5 Claims. (Cl. 6822) This application is acontinuation of our copending application Serial No. 55,672, filedSeptember 13, 1960, now abandoned.

The present invention relates to the treatment of tubular knittedfabrics, and more particularly to novel and improved method and meansfor continuously dyeing tubular knit material in a manner to provide adyed tubular fabric free of edge marks.

The dyeing of fabrics is desirably carried out on a continuous basis, bydirecting a web of bleached or scoured material through a bath of dyeliquor and uniformly impregnating the material with the dye. Suchcontinuous dyeing has been carried out successfully with wovenmaterials, for example, in which the material to be treated is inopen-width form (i.e., in the form of a single-layered web). However,notwithstanding its many potential advantages, continuous dyeing has notbeen applied successfully, heretofore, to the treatment of tubular knitfabrics, although the industry has attempted for many years to developcommercially practicable methods to do so.

In large part, at least, tubular material has been incapable of beingsuccessfully continuously dyed, theretofore, by reason of an inabilityto obtain uniformity of dyeing, and hence of color, throughout theentire extent of the tubular material. Specifically, tubular material isnormally treated in flattened, two-layered form, which gives rise tosubstantial problems in connection with uniform penetration of the dye,particularly at the edges of the material. Thus, continuously dyedtubular material has been characterized, heretofore, by edge marks, orareas at the edges of the tube where the coloring is either lighter ordarker than over the remaining area. Such edge marks render the materialunsuitable for commercial use, as they result in unwanted continuouslines or streaks in a lengthwise direction along the edges of the fabrictube. And while these streaks are initially at the edge, which in itselfis very undesirable, further processing of the tubular fabric causes thestreaks to appear at any point in the finished fabric, because of fabricreorientation, which creates new edges, and this is wholly intolerable.Moreover, with tubular fabric, both sides or surfaces must be absolutelyuniform as regards color shading since, as mentioned, the two principalsides of the fabric may and usually will be reoriented during furtherprocessing.

In accordance with the present invention, novel arrangements areprovided for delivering, in a continuous, controlled process, acommercially acceptable dyed tubular knitted fabric, free of so-callededge marks, color variations on opposite sides, and other commondefects. To this end, the invention provides an improved apparatus fortreating tubular knitted fabric, whereby the material is penetrateduniformly and thoroughly by the dye liquor on both principal layers ofthe fabric tube and at the doubled-over edges, whereby edge mark-s,color variations on opposite surfaces, and other defects, at the edgesor folds of the material or elsewhere, are effectively eliminated.

Generally stated, the method of the invention involves the firstimportant step of laterally distending the tubular ice knitted fabricand setting it to predetermined width. The uniformly set fabric is thensubmerged in a bath of dye liquor and there subjected to a succession ofsqueezings under concentrated pressure. During the squeezings, thefabric is maintained continuously and wholly submerged in the dye bath,and the opposite sides of the fabric are alternately exposed to the dyeliquor. At the same time, the generally elastic and dimensionallyunstable fabric is maintained under constant dimensional control toprovide uniform fiber and stitch conditions, which promotes uniformpenetration and acceptance of the dye. The succession of submergedsqueezings is such in number and character as to reliably assurecomplete and uniform dye penetration, even at the doubledover edgeportions of the fabric tube. The thus uniformly and thoroughlyimpregnated fabric is immediately thereafter, and while being maintainedunder complete dimensional control, passed through a resilient nip toreduce the dye liquor content to a predetermined uniform level.

As one of the more specific but significant aspects of the invention,the tubular knitted fabric is directed into a dye bath and passedthrough a series of concentrated pressure nips for successivelysqueezing and releasing the fabric a plurality of times while the fabricremains wholly submerged in the dye bath and under continuousdimensional control. Immediately thereafter the fabric is passed througha lower pressure nip, which controllably limits the amount of uniformlypenetrated dye liquor to be retained in the fabric. Throughout thetreating sequence, advantageously from the first to the final pressurenip, the normally elastic and easily distortable fabric is maintainedcontinuously in control contact with dimensionally stable surfaces, sothat the internal structure and geometry of the fabric is kept uniform,as is the ability of the fabric to receive and retain dye uniformly.Further, during the successive, submerged squeezin-gs of the fabric insubmerged pressure nips, opposite sides of the tubular fabric arealternately exposed to the dye bath (one side always being in contactwith a surface) so that desired uniformity of dye penetration fromeither side is obtained.

As a further specific feature of the invention, the submerged nipsadvantageously are comprised of cooperating pairs of non-resilientrollers capable of applying concentrated nip pressures to the submergedtubular knitted fabric. The sets of rollers are so arranged, accordingto the invention, that alternate (intermediate) rollers are urgeduniformly into concentrated pressure contact with two adjacent rollersin a way that assures substantial uniformity of the successiveconcentrated nip pressures.

Advantageously, means are provided whereby the tubular fabric isdirected downwardly into the dye bath and is passed through a firstsubmerged, concentrated pressure roller nip, while still moving in adownward direction. The roller nip completely closes the tube andprevents the entrapment of air inside the fabric tube. The sponge-likeaction, realized as the fibers are squeezed and subsequently released inthe submerged, concentrated pressure nips, assures thorough eliminationof air from the fibers and thorough and uniform penetration of thefibers by the dye liquor.

Another specific feature of the invention resides in the provision, incombination with novel facilities mentioned for imparting a uniformlypenetrated excess of dye, of im- I proved, resilient roller meansforming a lower, controlled pressure nip at the exit end of the dyestation. As the material emerges from the dye bat-h, it is passeddirectly and while still under dimensional control through the nipformed by the resilient rollers, whereby excess dye is removed from thematerial in a uniform and desirable manner. In this respect, it has beenfound that the non-resilient rollers.

nature of the surfaces forming the resilient nip may be an importantfactor, since edge marks may result if the roller surfaces are too softor too hard.

A further important feature of the invention resides in the provision,in means generally as above described for continuously dyeing fabrics,of improved arrangements for uniformly preconditioning the fabric priorto its passage through a dye station, to the end that the fabricentering the dye station is uniformly conditioned as to temperature andwater content, so that all portions of the fabric may be acted uponuniformly by the dye. In the treatment of wet goods, for example, thematerial entering and continuously passing through the dye bath has arelatively short period in which to be acted upon by the dye, andvarious non-unitormities in the goods will show up as colorimperfections in the dyed material. Accordingly, the present inventionprovides for the continuous treatment of the goods, prior to dyeing, torender uniform the water content thereof. Advantageously, this isaccomplished in a manner and by an apparatus similar to that used in theactual dyeing of the goods. Thus, the material is passed in a downwarddirection into a water bath, through a series of submerged concentratedpressure n-ips advantageously formed by contacting, friction-driven,Immediately thereafter the fabric is passed through a pair of extractingrollers. While passing through the submerged nips, the fabric issubjected to a series of high pressure squeezing and releasing actions,whereby the fabric takes up a uniform excess of Water. The excess wateris thereupon removed by the extracting roller, whereby the emergingmaterial contains a uniformly distributed, predetermined quantity ofWater and is conditioned to accept the dye liquor uniformly.

The invention also provides for the preconditioning of wet material bycausing it to absorb, prior to dyeing, a uniform quantity of water at atemperature which approximates or exceeds that of the dye liquor itself.Accordingly, the material entering the dye bath is as close aspracticable to the controlled temperature of the dye liquor. This is animportant factor in the achieving of high quality, uniform dyeing of wetgoods on a continuous basis, since dye penetration is affected bytemperature and non-uniformities may be expected where constantconditions do not prevail.

In the treatment of wet goods, as in the treatment of substantially drygoods, the fabric is caused to have uniform dimensions and conditionsduring the preconditioning water treatment, to assure uniformity ofwater penetration and absorption. To this end, the material is laterallydistended or spread to a predetermined width and uniform condition,prior to entry into the treating bath, and this condition is carefullymaintained during passage of the material through the treating bath byreason of constant contact of the material with surface portions of thenon-resilient friction-driven rollers. The preconditioned materialemerging from the water bath is again set to predetermined width or,where advantageous or expedient, the material may be directedimmediately into the dye bath while maintaining the uniform conditionsof width and tension, etc.

The teachings of the invention are also applicable to advantage inconnection with the treatment of materials in successive stages, wherethe first stage, or perhaps an intermediate stage, is not a watertreatment but is a treatment with active solution. Thus, in conjunctionwith a dyeing treatment, it may be desirable to precondition thematerial uniformly with a penetrant or other pretreatment solution.'Further, it may be desirable and advantageous to carry out the dyeingoperation in two or more distinct stages, either with or without a stepinvolving water or other preconditioning solution.

In connection with the treatment of dry materials, the inventionprovides for preconditioning of the material by steaming the materialwhile distending it to uniform width,

prior to entry of the material into the dye bath or into apreconditioning water bath. By thus steaming the material, whiledistendin-g it to predetermined, uniform width, the material is not onlyrendered highly uniform in structure and therefore capable of uniformlyaccepting the dye or preconditioning bath, but is uniformly conditionedfrom the standpoint of heat and moisture content, which aids importantlyin bringing about uniformity of dye penetration. The material may alsobe spread to an extra wide width to enable the rate of dye penetrationto be increased.

For a better understanding of the invention, and for a furtherdiscussion of the above and other novel and advantageous featuresthereof, reference should be made to the following detailed descriptionand to the accompanying drawings, in which:

FIG. 1 is an elevational view of an apparatus incorporating theinvention and for use in carrying out the method of the invention; I

FIG. 2 is a top plan view of the apparatus of FIG. 1;

FIG. 3 is an enlarged, fragmentary, cross-sectional view taken generallyon line 33 of FIG. 2; and

FIG. 4 is a simplified schematic representation of a processing line,incorporating apparatus as illustrated in IFIG. 3, for treating wetgoods.

Referring now to the drawings, the reference numeral 10 designates,generally, a representative form of combination spreader and propellingdevice, which may be of the type described in the S. C-ohn et a1. UnitedStates Patent No. 2,385,402, for example. The spreader 10 is positionedto receive tubular material from a prior processing station, as part ofa continuous process, and uniformly conditions the material and distendsit laterally to a predetermined width. The spreader also advances thematerial toward a dyeing station, designated by the reference numeral11. The material received by the spreader 10 may be bleached or secured,and may be in either wet or dry form. If the material is in dry form, itis advantageous to provide steamers 12 in association with the spreader10, so that the material is steamed in connection with the operation ofdistending it to a predetermined width. The steaming not only sets thefabric in its distended form and enables the material to be renderedstructurally uniform, but also heats it uniformly and imparts uniformmoisture thereto, all of which importantly alfect the uniformity ofdyeing. It is uniformly necessary, of course, for the fabric to bepresented to the dye bath in fiat form and in a uniform, geometriccondition.

If the fabric is taken directly from a bleaching operation, for example,and is in wet form, a pair of squeegee rolls 13 may be provided toremove as much of the residual treating liquids as possible from thematerial after it is passed over the spreader 10. Where the material isreceived in wet form, the steamers 12 usually may be omitted, but theymay be utilized to advantage in elevating the temperature of the fabric.By spreading the wet material to a predetermined, uniform width, thevarious tensions in the material are rendered substantially uniform,enabling dye penetration to be effected with desired uniformity, as willbe described.

The illustrated spreader device 10 consists of a pair of belts 14, 15supported within the fabric tube by a frame 16 and driven by a pair ofedge rolls 17, 18. The frame 16 may be adjusted to a predeterminedwidth, to stretch the fabric width-wise to a predetermined extent, andthe fabric is propelled forward over the spreader by means of the belts14, 15 driven by the edge rolls 17, 18. In the illustrated arrangement,the speed of the fabric on opposite sides of the edge rollers 17, 18 isthe same.

In the treatment of dry fabric, the fabric is subjected to steaming, bymeans of the steamers 12, while on the. spreader 10. This lubricates thefibers of the material and enables them to reorient as necessary. Suchlubrication is not required, of course, where the spread material is wetfrom prior treatments, such as bleaching, etc. In addition, the steamersuniformly condition the material with respect to temperature andmoisture content.

In the form of the invention shown in FIGS. 1-3, the fabric travels fromthe spreader to a dye bath maintained in a reservoir 19. If wet fabricis treated, the fabric is passed between the squeegee rollers 13, duringits travel between the spreader and the dye bath, so that excess wateror other liquid is removed from the material and a desired liquidcontent in the material is achieved. The fabric thus conditioned isimmersed in the dye bath and subjected therein to an action resulting inthe thorough and uniform penetration of the dye, in a manner to bedescribed.

Referring now to FIG. 3, the reservoir 19 of the dye ing apparatus issupported on a frame 20 and provided with an overflow pipe 21, which, incombination with appropriate dye inflow means (not shown), maintains thedye bath 22 at a predetermined level. Advantageously, a constant,circulating inflow of dye liquor is provided to assure uniformity of thedye mixture as well as to maintain the dye at a precise, predeterminedlevel in the reservor. Uniformity of the dye level is considered to be afactor of prime significance in the obtaining of uniform dyeing results.

The fabric F travels over the dye bath 22, at the entry or right handside thereof and passes over a guide roller 23 mounted in a frame 24 ata level such that at least part of the roller is exposed above the levelOtf the bath.

Mounted in the frame 24, below the level of the bath, are non-resilientpressure rollers 25, 26, which advantageously are arranged to rotatefreely in the frame. Spaced above and to the left of the pressurerollers 26, so as to be only partly immersed in the dye bath 22, is anextracting roller 27 which advantageously is of relatively largediameter and has a surface covering 28 of resilient material, as will bedescribed. The roller 27 is mounted in the frame 24 and is connected tosuitable drive means D (FIG. 2).

As illustrated in FIG. 3, the rollers 25, 26 and 27 are arrangedsomewhat in a line, and each is spaced a predetermined distance from theadjacent roller or rollers. Mounted below the rollers 25-27 andpositioned generally in the spaces between those rollers arenon-resilient pressure rollers 29, 30, which advantageously are the samediameter as the pressure rollers 25, 26, which diameter is somewhatlarger than the spaces between the rollers 25, 26 and 26, 27.

In accordance with one specific aspect of the invention, the pressurerollers 29, 30 are suspended at their opposite ends by arms 31, 32,which are pivotally connected to a yoke 33 at points 34, 34'. The yoke33 is, in turn, connected to control means, such as a lever 35, by apivot 36 located substantially centrally between the pivots 34, 34. Thelever is pivoted at 37 on the main frame 24 and has mounted at one end ahand lever 38, for example, by means of which the lever 35 may bemanipulated. The hand lever 38 cooperates with a bracket 39 havingtherein a plurality of notches 40 which receive the hand lever 38 andlock it in any of a plurality of positions.

By appropriate manipulation of the hand lever 38, the rollers 29, 3% maybe moved toward and away from the pressure rollers 25-27. Thus, tothread the fabric F through the machine the hand lever 38 is movedforward to lower the pressure rollers 29, 30. The fabric F is thenthreaded first between the rollers 25, 29, next between rollers 29, 26,then between rollers 26, 30 and, finally, between rollers 30, 27. Thehand lever 38 is then drawn rearwardly and engaged in one of the notches40. The rollers 29, 30 are thereby drawn tightly against the rollers25-27, forming therewith a plurality of submerged roller nips throughwhich the fabric passes. By suspending the yoke 33 centrally between thepivot points 34, 34', it is assured that the rollers 29, 30 will engagethe rollers 25-27 with uniform pressure, so that each of the severalroller nips formed by the roller pairs 25 and 29, 29 and 26, and 26 and30 is substantially the same as regards nip pressure. Advantageously,the hand lever 38 is formed of steel rod, for example, providing for acertain measure of springiness or yield. Accordingly, once the rollers29, 30 are brought into engagement with the rollers 25-27, the nippressure may be regulated by deflecting the hand lever 38 and locking itin a deflected position by means of the notched bracket 39.

In accordance with one of the specific aspects of the invention, thefirst pressure nip, through which the fabric F is passed substantiallyimmediately after it enters the dye bath 22, is so oriented that thefabric passes through the nip while moving in a generally downwarddirection. In the illustrated apparatus, the first submerged pressurenip is formed by the non-resilient rollers 25, 29 and the fabric Fpasses directly to this nip from the guide roller 23. The arrangement ofthe first nip in this manner is advantageous in that the fabric issqueezed flat under forcible pressure to displace any air which may betrapped within the tube. Generally, a relatively large volume of air isexpelled from the material at the first nip and it is important torelease the air from above the nip to facilitate escape of the air, asindicated by the series of bubbles at 4 1. Otherwise, the air is apt tobecome trapped within the fabric tube.

As the fabric passes through the series of submerged nips, including thefirst nip, the fabric is compressed forcibly and with highlyconcentrated pressure by the nonresilient rollers 25, 26, 29, 30, sothat air and liquid is thoroughly forced out of the fibers in aneffective and uniform manner. As the fabric emerges from each pressurenip, the concentrated nip pressure is suddenly released from the fabricand the dye liquor is drawn into the fibers to replace the air andliquid expelled therefrom during passage through the nip. This resultsin a spongelike action in the fabric, whereby air and liquid arerepeatedly and thoroughly expelled under concentrated nip pressure fromthe fabric and dye liquid is then drawn back into the fibers topenetrate all portions of the fabric in a highly effective and uniformmanner.

In accordance with one of the significant aspects of the invention, thefabric traveling through the series of submerged, concentrated pressurenips formed by the nonresilient rollers 25, 26, 29, 30 is at all timesmaintained in edge-to-edge control contact with at least one of therollers. Accordingly, the tubular knit fabric, which is inherentlyelastic in character and easily distorted, is effectively retained inits original dimensions, preventing gathering and wrinkling of thefabric and assuring maintenance of the uniform tension conditions in theyarns of the fabric. In this respect it is a feature of the inventionthat the tubular knit fabric is maintained constantly under dimensionalcontrol from the point of its entry into the first concentrated pressurenip, formed by rollers 25, 29, to the point of emergence of the dyedfabric from the extraction nip, constituting the last instance ofworking of-the fabric during the dyeing process. Advantageously, this isaccomplished by maintaining the fabric in edgeto-edge control contactwith roller surfaces throughout. By this means, the unstable, easilydistortable fabric is maintained reliably and controllably uniformthroughout the working of the fabric in the presence of the dye liquid,so that conditions are proper for uniform acceptance of the dye by thefabric.

In addition, and as another important facet of the invention, thetubular knitted fabric traveling through the series of concentratedpressure working nips has its opposite sides alternately exposed to thedye liquid. In this respect, the opposite surfaces of tubular knittedfabric in process do not represent front and back, as is the case withwoven fabrics and other materials handled in open width form, but boththe top and bottom surfaces are outside surfaces of the finished fabric.As a result, unless both surfaces are dyed to an identical shade, thefinished product is inferior, if not useless. Thus, in the system of theinvention, the concentrated pressure working nips, and the non-resilientrollers forming them, are wholly submerged in the dye liquid so that, asthe fabric passes through the nips in sequence, with one surface alwaysin contact with a roller, the opposite sides of the fabric arealternately exposed to the dye bath.

In the illustrated form of the invention, the covered roller 27 isdriven by the drive means D, and the rollers 25, 26 and 29, 30 aredriven at corresponding peripheral speeds by reason of the frictionalcontact between the series of rollers and the fabric passing between theroller nip. In this manner, lengthwise tensions on the material, whichmight otherwise change in passing the material through one or moreroller nips, are maintained at a highly uniform level.

In accordance with the invention, the successive high pressuresqueezings of the uniformly conditioned material, as it passes throughthe successive, submerged working nips in the dye bath, are such, innumber and effectiveness, as to penetrate the fabric uniformly with anexcess of the dye liquor. Moreover, and particularly as a result ofworking in non-resilient submerged nips, the extreme edge portions ofthe fabric, where the material curves around from one flat plane toanother, are thoroughly penetrated by an excess of dye, and thisconstitutes an important accomplishment of the invention as it enablesthe finished product to be free of edge marks characteristic of materialattempted to be dyed continuously by known procedures and with knownequipment.

After the fabric F has passed through the series of submerged workingnips formed by the rollers 2527, 29, 30, the fabric travels upward,around the surface of the partly submerged roller 27, and through anextracting nip 42 formed by the roller 27 and a similar roller 43located directly above. The rollers 27, 43 are provided with coverings28, 44 of resilient material, advantageously rubber, and, as the fabricpasses through the nip 42, pressure is applied by the rollers 27, 43, toextract excess dye uniformly from the fabric, leaving a uniform,predetermined amount of the dye in the fibers.

In accordance with one aspect of the invention, the operation ofextracting the excess dye from the fabric is carried out in a mannercalculated to assure uniformity of dye coloring throughout the entirearea of the fabric, including its edges. At the extreme edges of thefabric, the material curves around, and narrow strips at the extremeedges of the material may not be acted upon by the extracting rollers inthe same manner as the flat surfaces of the fabric. However, we havefound that, by imparting to the surfaces of the rollers 27, 43 theproper degree of resilience, so that the rollers are neither too softnor too hard, the extracting step may be carried out with substantialuniformity throughout all areas of the material, avoiding edge marks andother defects. Specifically, it has been found that superior results areachieved by providing the rollers 27, 43 with surface coverings 28, 44formed of rubber having a density approximating 72 durometer. It isanticipated that the operative range of rubber density would extendsomewhat above and below 72 durometer, but it is presently believed tobe important, insofar as the extracting operation is concerned, toutilize rollers having surface characteristics similar to those ofrubber whose density is in the range of 72 durometer. Of course, it isnecessary to the realization of proper results in the extracting stagethat the fabric previously be thoroughly and uniformly impregnated withdye liquid, as by the described series of high pressure working nips,and that the dimensional uniformity and control of the fabric bemaintained until completion of the extracting action at the nip 42.Thorough dye penetration in excess quantities, reliably achieved as inaccordance with the invention, materially improves the prospect ofcarrying out the extracting operation in a manner such that the finishedproduct is free of edge marks, etc.

One of the advantageous aspects of utilizing extracting rollers havingrelatively resilient surfaces is that, due to deformation of the surfacematerial, the nip 42 is relatively broad, in a direction lengthwise ofthe fabric. This assures thorough extraction of the excess dye, as wellas a sustained uniformity of action on the material. In addition, thecharacteristics of the surface material of the extracting rollers have asubstantial effect on the treatment of the material at the extremeedges. Thus, if the extracting rollers have hard surfaces, the materialwill be subjected to increased pressure at the extreme edges while, ifthe surface material is too soft, it may deform and close about theedges of the material to an undesirable extent. In either case,undesirable edge marks on the material will result.

The pressure at the extracting nip advantageously is controlled in arelatively precise manner by mounting the upper roll 43 on a lever 45pivoted on the frame 24 by means of a pin 46. The free end of the lever45 may have attached thereto a suitable spring device 47, for example,capable of relatively precise adjustment, so that the extracting rollpressure may be adjusted in an accurate manner. A typical adjustingarrangement suitable for this purpose is illustrated in the S. Cohn etal. United States Patent No. 2,729,003, for example.

After the fabric F leaves the dye bath and passes through the extractingnip 42, subsequent treatments usually are applied, depending on thenature of the dyeing or processing. For example, where direct dyes areused, the fabric usually is directed to a salt bath, to salt in thecolor, then to a rinse and perhaps to other treating stations including,for example, a softening bath. The material may then be dried and curedor otherwise treated, as may be desired.

The method and apparatus above described are particularly useful in thetreatment of dry fabrics (using the steamers 12) and may be usedsuccessfully in the treatment of wet fabrics (using the squeegee rollers13). However, for controllably superior results in the treatment of wettubular knitted fabrics, the invention, as one of its important aspects,contemplates the provision of arrangements for uniformly andcontrollably preconditioning the fabric, prior to dyeing, enabling thedyeing operation itself to be carried out with desired, superioruniformity.

In this respect, it has been found that, in continuous dyeing of wetfabric, where the material has a relatively short period of exposure tothe dye liquor, precise uniformity of water content of the fabric isimportant to the achievement of uniformity of dyeing. Thus, whereas thesystem of FIG. 1 may be adequate for the treatment of wet material whosestarting or initial water content is fairly uniformly excessive, suchrelatively ideal conditions may not be present always and the treatmentmay have to be carried out with material which is wet, but notcontaining either a uniform or an excess quantity of water, or with drymaterial which it is desired to wet prior to immersion in the dye bath.

Referring now to FIG. 4, there is shown a processing line especiallyarranged, in accordance with the invention, for the treatment of wettubular knitted fabric in a manner to achieve reliably superior, uniformdyeing of wet material on a continuous basis. The starting material 50may be in wet form, as received from prior processing operations, suchas bleaching and subsequent, related treatments, and the material inthis form is, in accordance with the invention, passed over a spreader51, which may correspond in construction and operation to the spreader10 of FIG. 1. While passing over the spreader 51, the fabric 50 isdistended to a predetermined uniform width, and desired, uniformconditions of tension are imparted to the material.

Advantageously, as the fabric leaves the exit side of the spreader 51 itis passed between squeegee rollers 52, which remove a substantial amountof excess liquid from the material. This usually is desirable, since theliquid contain-ed in the fabric may contain chemicals from priortreatments, whose presence in the material in substantial quantities mayundesirably affect the further treatment thereof. If the liquidinitially in the fabric is plain water, the squeegee rollers 52 may notbe required.

After the material 51 has been spread, and has passed through thesqueegee rollers 52, if used, it is directed into an impregnation unit53 containing water or other pre-treating solution. The unit 53advantageously is of the same construction as the dyer unit 11, of FIGS.1-3, the principal difference residing in the fact that the liquidcontained in the reservoir is water or other pretreating solution ratherthan dye liquor. The fabric passes downward into the solution andsuccessively through a series of wholly submerged high pressure workingnips formed by contacting, friction-driven, non-resilient rollers, allas clearly indicated in FIG. 3. At each working nip, solution and airare forcibly expelled from the fabric and, as the material emerges froma nip and is released by the roller, solution is drawn back into thematerial, thoroughly penetrating the fibers of the material. By reasonof the successive squeezing and releasing actions under concentratedpressures while the fabric remains submerged in the solution, a uniformexcess of the solution penetrates the entire body of a material.

As the fabric traveling through the solution is subjected to asponge-like action by successive squeezing and releasing operations, itis maintained in continuous contact with rollers so that the fabric doesnot tend to narrow down from its preset width. Moreover, as beforedescribed, the various rollers forming the submerged nips are driven byfrictional contact with each other, through the interposed material, sothat tensions in the material are not varied during the course of travelthrough the solution.

Material emerging from the pre-treating solution is uniformlyimpregnated with an excess quantity of solution, and this material ispassed through extractor rollers 54, corresponding to the rollers 27, 43of FIG. 3 and forming part of the impregnation unit 53. The action ofthe rollers 54 is such as to extract from the material the excessquantities of solution, leaving a predetermined, uniform quantityprecisely suited for subsequent dyeing of the material.

In accordance with one aspect of the invention, the solution in the unit53 is maintained at or above the temperature of the dye bath, to the endthat the wet material ultimately entering the dye bath is substaniallyat the temperature of the dye liquor. This is of special importance inthe continuous dyeing of wet materials, since non-uniform results wouldbe realized if cold wet fabric were introduced into the dye bath,particularly since there is only a short period of time in which toreach equilibrium temperature conditions while the material mov-esrapidly through the bath. Generally, the pre-treating solution (as thedye bath) is maintained at a predetermined tempenature, and suitableheating means, not specifically shown, are provided for this purpose.

In the system illustrated in FIG. 4, the solution-impregnated materialleaving the unit 53 is passed over a second spreader 55, which may be ofthe type before described. This spreader re-establishes precisegeometric control over the fabric. And, if desired, the material may beset at some other width calculated to provide a desired level of uniformtension for dyeing.

In certain cases, where adequate geometric control of the fabric isotherwise maintained, the second spreader may be eliminated altogether,and the solution-impregnated material taken directly into the dye bathfrom the extractor rollers 54.

The impregnated and otherwise preconditioned material, after spreadingif the unit 55 is employed, is directed into a dyer apparatus 56, which,for the purpose of this description, may be similar in all materialrespects to the dyer unit show-n in FIG. 3. The wet material enteringthe dye bath maintained in the unit 56 is, among other things, heatedsubstantially to the temperature at which the dye bath is maintainedwhich, in some cases, is near boiling. Suitable heating means, notspecifically shown, are of course provided in association with the unit56, as well as the unit 11 of FIG. 1, to maintain the dye bath at thedesired temperature.

Dyeing of the preconditioned, wet material in the unit 56 takes placesubstantially in the manner before described in connection with thesystem of FIGS. 1-3. The emerging, dyed material is highly uniform innature, free of edge marks and otherwise of high quality character.

In a system, such as shown in FIG. 4, the material may be subject to twoor more distinct treatment steps. In many instances, at least one ofsuch steps will be a Water pretreatment step, but it may be advantageousto carry out a plurality of separate treatment steps with or with out anadditional water pretreatment step. Certain dyes, for example, aretypically applied in a two stage process, and the system of theinvention may be utilized to carry out such a two stage process as partof a continuous operating line.

In connection with the treatment of dry goods, it is particularlyimportant to precondition the material by spreading it to uniform,predetermined width and steaming it while thus spread to impartstabilized structural uniformity thereto. Spreading of the material isalso important in the case of wet material, to set the material topredetermined width and to render it structurally uniform, but steamingof the Wet material normally is not required.

The new method represents a substantial advance in the art, by providinga method of dyeing tubular knitted fab-ric continuously to producecommercially acceptable dyed tubular knitted fabric free of edge marks.Thus, bleached or scoured fabric, taken in either a wet or dry state,may be passed continuously, in the form of a flat web of doubledmaterial, through the dyeing apparatus and directly to the subsequentprocessing stations, such as the salt bath and rinse, for example.Heretofore, it has been deemed impossible to dye tubular knittedmaterial on a continuous basis in a competitive manner productive ofcommercially acceptable finished fabric free of edge marks,notwithstanding that continuous dyeing has been done successfully formany years with woven fabrics. With the method and apparatus of theinvention, however, the various difficulties have been overcome in amanner assuring thorough and uniform penetration of the fibers by thedye liquor, followed by uniform extraction of excess dye.

One of the particularly important aspects of the invention resides inthe working of the tubular knitted fabric through a contacting series ofwholly submerged, nip rollers capable of applying substantialconcentrated working pressures to the fabric. The arrangement is suchthat the tubular knitted fabric is subjected to a succession of highpressure squeezing operations, to displace liquid and air, followed by aquick release of the concentrated squeezing pressure, to cause thefabric to draw the dye liquid thoroughly into all of its fibers. Theutilization of non-resilient rollers to form the series of working nipsis of particular advantage, in that it enables the working pressure tobe highly concentrated at the submerged working nip. This enables thefabric, in passing through a series of such high pressure nips, toabsorb a uniform excess of the dye liquida condition which has beenheretofore unattainable in a practical continuous operation with tubularknitted fabrics.

In conjunction with the utilization of a succession of high pressureworking nips, the rollers forming the working nips are arranged in acontacting series, so that at least one surface of the tubular knittedfabric is at all times in edgc-to-edge control contact with adimenisonally stable roller surface. Thus, the geometric conditions ofthe inherently elastic and unstable tubular knitted fabric are, to thegreatest practicable extent, maintained uniform and under effectivecontrol. This is particularly important to enable the tubular knittedfabric to accept the dye liquid in a uniform manner and is a factorwhich, prior to our invention, has not been adequately recognized andappreciated. Specifically, it is a feature of this invention that thetubular knitted fabric is maintained under dimensional control from thepoint of its initial entry into the first submerged working nip to thepoint of its emergence from the extracting nip, advantageously, bycontinuous edge-to-edge contact with roller surfaces. Accordingly, allof the working operations performed on the tubular knitted fabric in thepresence of the dye liquid are performed while the fabric is maintainedgeometrically stabilized.

As a further specific aspect of the invention, the tubular knittedfabric, while passing through the series of submerged working nips andwhile having one surface maintained in control contact with adimensionally stable roller surface, has its opposite sides alternatelyexposed to the dye liquid. In this respect, it was recognized that theability of the fabric to absorb the dye liquid in the region of thesurface thereof in contact with a dimensionally stable roller surfacemay be limited relative to the opposite surface. Accordingly, provisionsare made in accordance with the invention to cause first one side andthen the other of the fabric to be in control contact with a rollersurface, as the fabric progresses through the series of submergedworking nips. The alternately noncontacting surfaces of the fabric thusare exposed successively to the dye liquid so that, in the course of thesubmerged working of the fabric, both sides of the fabric are exposed tothe dye liquid.

The various aspects of the present invention particularly recognize andaccommodate the fact that all of the exposed surfaces of a tubularknitted fabric constitute outside surfaces of the finished fabric, asdistinguished from the typical woven fabric, for example, in which onesurface is the outside and one surface is the inside. Thus, in thedyeing of tubular knitted fabric, it is absolutely essential that boththe top and the bottom, and also the edge extremities, assume exactlyidentical dye shades. Any shade differential between sides, or any marksor lines along the edge extremities, will render the fabric practicallyworthless, since the consumer obviously desires color uniformity in thefinal garment. This is particularly true in view of the fact that theedges of the fabric during the dyeing operation may not be the edges ofthe fabric at a later stage in processing, so that a shade differentialline or an edge mark may ex tend along a principal fiat surface of thefinished fabric tube.

A significant achievement of the present invention is the ability toimpart to the tubular knitted fabric, during its continuous passagethrough a dye bath, a uniform excess of the dye liquid in all of thefibers and yarns of the fabric, including the edge extremities andincluding the top surface to the same extent as the bottom surface. Thisgreatly reduces the criticality of the subsequent extracting operation,by which the excess dye is removed from the fabric to achieve a highquality, uniform product. A further significant achievement resides inthe ability to achieve thorough, uniform penetration in a relativelyshort course of fabric travel, so that the setto-width and geometricallystabilized fabric tube may be maintained under geometric controlthroughout.

The most important ultimate advantage of the new method and apparatusresults from the fact that the dye station may be incorporated in acontinuous tubular knitted fabric processing line, so that the fabricmay be subjected to an entire series of processing operations on ahigh-speed, continuous basis. Heretofore, dyeing of tubular fabric hasbeen carried out on a batch basis, usually by placing lengths or stringsof the fabric in a dye vat. This has involved an interruption of theprocessing sequence and has, in addition, involved additional operatingsteps in preparing the fabric for the dye vat and subsequentlyconditioning it for further continuous processing.

It should be understood that the specific method and means hereinillustrated and described are intended to be representative only, ascertain changes may be made therein without departing from the clearteachings of the disclosure. Accordingly, reference should be made tothe following appended claims in determining the full scope of theinvention.

We claim:

1. Apparatus for continuously and uniformly impregnating tubular knitfabric with a dye liquid to provide dyed tubular knitted fabric free ofedge marks, which comprises (a) a reservoir for maintaining a bath ofthe liquid at a predetermined level,

(b) means adjacent the entry end of the reservoir for guiding thetubular fabric and presenting it in flat form into the bath,

(c) a plurality of pressure rollers below the surface of the bath andforming a succession of submerged nips arranged successively to receiveand apply concentrated pressure to the fabric,

(d) said pressure rollers being wholly submerged in said bath, wherebysaid fabric remains continuously and wholly submerged in said bath whilepassing through said succession of submerged nips,

(e) the succession of submerged nips comprising a plurality ofnon-resilient rollers forming concentrated pressure nips,

(f) certain of the non-resilient rollers being mounted for rotation onnormally fixed axes and being spaced from each other,

(g) the remainder of the non-resilient rollers being controllably andforcibly movable into and out of the spaces formed between the fixedrollers,

(h) the movable rollers being suspended at each end by pairs of supportarms,

(i) the support arms being pivotally secured to yokes at opposite endsof the rollers,

(j) the yokes being mounted for pivoting movement about axessubstantially centrally between the pivot axes of the support arms,

(k) means being provided for controllably moving the pivot axes of theyokes toward and away from the normally fixed rollers, and

(1) an extracting nip mounted adjacent the exit end of the reservoir andabove the level of the bath and comprising a pair of extracting rollshaving resilient outer surfaces,

(m) said pressure rollers being mounted in a contacting series, wherebythe fabric is caused to be in edge-to-edge control contact with adimensionally stable surface while passing through said submerged nips.

2. Apparatus for continuously and uniformly impregnating tubular knittedfabric with a dye liquid to provide 60 dyed tubular knitted fabric freeof edge marks, which comprises (a) means forming a reservoir for the dyeliquid,

(b) liquid level control means for maintaining a bath of the dye liquidat a predetermined constant level in said reservoir,

(c) means adjacent the entry end of the reservoir for engaging andguiding the tubular knitted fabric, distending it laterally to fiattwo-layer form and to predetermined uniform width, and substantiallydirectly presenting the fabric in flat two-layer form into the bath ofdye liquid,

(d) a plurality of pressure rollers forming a succession of submergedsqueezing nips arranged successively to receive and apply concentratedsqueezing pressure to the tubular knitted fabric,

(e) said pressure rollers being disposed in said reservoir and at alevel such that at least alternate ones of the pressure rollers and allof said squeezing nips are below the predetermined constant level ofsaid liquid level control means,

(f) means effective to drive said pressure rollers in a direction toguide and advance said tubular knitted fabric about said pressurerollers and through said squeezing nips while maintaining said tubularknitted fabric continuously and uninterruptedly below the predeterminedconstant level of said liquid level control means and thereforesubmerged in said dye liquid,

(g) an extracting nip located adjacent the exit end of said reservoirand above the level of said liquid level control means and comprising apair of extracting rolls having resilient outer surfaces,

(h) means mounting one of said extracting rolls above the other,

(i) means mounting the lower one of said extracting rolls at a levelsuch that at least part, but less than all, of its surface is below thepredetermined constant level of said liquid level control means andtherefore submerged in said dye liquid,

(j) said lower extracting roll and the last one of said pressure rollersbeing so mounted and disposed that transference of said tubular knittedfabric from said last pressure roller into contact with said lowerextracting roll is effected below the predetermined constant level ofsaid liquid level control means and while said fabric remainscontinuously and uninterr-uptedly submerged in said dye liquid,

(k) means supporting said pressure rollers in a contacting seriesdisposed and arranged to guide and direct said tubular knitted fabricsinuously about said rollers to expose the opposite layers of the fabricalternately to the dye bath, and

(1) means comprising said pressure rollers for guiding and directing thetubular knitted fabric continuously and uninterruptedly in edge-to-edgedimension stabilizing contact with dimensionally stable roller surfacesat all times while passing through said submerged squeezing nips, fromat least the first to the last such submerged nip.

3. An apparatus according to claim 2, further characterized by (a) thepartially submerged lower one of said extracting rolls being mounted inpressure contacting relation with one of said pressure rollers,

(b) external drive means being provided for rotating said partiallysubmerged extracting roll,

(c) the other of said extracting rolls and said pressure rollers beingdriven from said partially submerged extracting roll and throughinterposed layers of tubular knitted fabric passing through saidsqueezing and extracting nips.

4. Apparatus for continuously and uniformly impregnating tubular knittedfabric with a dye liquid to provide dyed tubular knitted fabric free ofedge marks, which comprises (a) means forming a reservoir for the dyeliquid,

(b) liquid level control means for maintaining a bath of the dye liquidat a predetermined constant level in said reservoir,

() means immediately adjacent the entry end of the reservoir forlaterally distending the tubular knitted fabric and presenting it inflat two-layer form and at a predetermined uniform width to the bath ofdye liquid and guiding and directing it downwardly into said dye liquid,

(d) a plurality of pressure rollers forming a sucession of submergedsqueezing nips arranged successively to receive and apply concentratedsqueezing pressure to the tubular knitted fabric,

(c) said pressure rollers being disposed in said reservoi-r and at alevel such that at least alternate ones of the pressure rollers and allof said squeezing nips are below the predetermined constant level ofsaid liquid level control means,

(f) means effective to drive said pressure rollers in a direction toguide and advance said tubular knitted fabric about said pressurerollers and through said squeezing nips while maintaining said tubularknitted fabric continuously and uninterruptedly below the predeterminedconstant level of said liquid level control means and thereforesubmerged in said dye liquid,

(g) the pressure rollers forming the first of said squeezing nips beingmounted and arranged in said reservoir to receive the presented tubularknitted fabric traveling in a downward direction into said bath toaccommodate expulsion and upward escape of air from the fabric as thefabric tube is closed and squeezed in said first nip,

(h) an extracting nip located adajacent the exit end of said reservoirand above the level of said liquid level control means and comprising apair of extracting rolls having resilient outer surfaces,

(i) means mounting one of said extracting rolls at a level such that atleast part, but less than all, of its surface is below the predeterminedconstant level of said liquid level control means and thereforesubmerged in said dye liquid,

(j) said one extracting roll and the last one of said pressure rollersbeing so mounted and disposed that transference of said tubular knittedfabric from said last pressure roller into contact with said oneextracting roll is effected below the predetermined constant level ofsaid liquid level control means and while said fabric remain-scontinuously and uninterruptedly submerged in said dye liquid,

(k) means supporting said pressure rollers in a contacting seriesdisposed and arranged to guide and direct said tubular knitted fabricsinuously about said rollers to expose the opposite layers of the fabricalternately to the dye bath, and

(1) means comprising said pressure rollers for guiding and directing thetubular knitted fabric continuously and uninterruptedly in edge-to-edgedimension stabilizing contact with a dimensionally stable roller surfaceat all times while passing through said submerged squeezing nips, fromat least the first to the last such submerged nip.

5. Apparatus for continuously and uniformly impregnating tubular knittedfabric with a dye liquid to provide dyed tubular knitted fabric free ofedge marks, which comprises '(a) means forming a reservoir for the dyeliquid,

( b) liquid level control means for maintaining a bath of the dye liquidat a predetermined constant level in said reservoir,

(c) means adjacent the entry end of the reservoir for presentinglaterally distended tubular knitted fabric in flat two-layer form and ata predetermined uniform width to the bath of dye liquid and guiding anddirecting it downwardly into said dye liquid,

(d) a plurality of relatively small diameter, substantiallynon-resilient pressure rollers forming a succession of submergedsqueezing nips arranged successively to receive and apply concentratedsqueezing pressure to the tubular knitted fabric,

(e) said pressure rollers being disposed in said reservoir and at alevel such that at least alternate ones of said pressure rollers and allof said squeezing nips are below the predetermined constant level ofsaid liquid level control means,

(-f) means effective to drive said pressure rollers in a direction toguide and advance said tubular knitted fabric about said pressurerollers and through said squeezing nips while maintaining said tubularknitted 15 fabric continuously and uninterruptedly below the thepredetermined constant level of said liquid level control means andtherefore submerged in said dye liquid,

(g) an extracting nip located adjacent the exit end of said reservoirand above the level of said liquid level control means and comprising apair of relatively large diameter extracting rolls having resilientouter surfaces,

(h) means mounting one of said extracting rolls at a level such that atleast part, but less than all, of its surface is below the predeterminedconstant level of said liquid level control means and thereforesubmerged in said dye liquid,

(i) said one extracting roll and the last one of said pressure rollersbeing so mounted and disposed that transference of said tubular knittedfabric from said last pressure roller into contact with said oneextracting roll is effected below the predetermined constant level ofsaid liquid level control means and while said fabric remainscontinuously and uninterruptedly submerged in said dye liquid,

(j) means supporting said pressure rollers in a contacting seriesdisposed and arranged to cause said tubular knitted fabric to travelsinuously about said rollers to expose the opposite layers of the fabricalternately to the dye bath,

(k) means comprising said pressure rollers for guiding and directing thetubular knitted fabric continuously and uninterruptedly in edge-to-edgedimension stabilizing contact with a dimensionally stable roller surfaceat all times while passing through said submerged squeezing nips, fromat least the first to the last such submerged nip, and

(1) means supporting one of said extracting rolls in pressure contactingrelation with the last pressure roller of the contacting series thereof,whereby to form an additional submerged squeezing nip constituting thelast of the series thereof.

References Cited by the Examiner UNITED STATES PATENTS 238,514 3/1881McAllister 689 786,264 4/1905 Butterworth 6822 1,893,197 1/1933 Cohn815l 1,979,818 11/1934 Baker 68-9 X 2,045,755 6/1936 Cohn 8-1512,239,636 4/1941 Weiss 6822 X 2,364,838 12/1944 Williams 6822 2,382,7268/1945 Korte 6822 2,385,402 9/1945 Cohn et al. 26-55 2,441,308 5/1948Bond 6843 X 2,445,504 7/1948 Williams 8151 2,724,254 11/1955 Zanger 68222,729,003 1/1956 Cohn et al. 38-52 2,849,784 9/1958 Adams 68-43 X2,904,981 9/1959 Macomson 8-159 X 3,036,359 5/1962 Cocker 6822 X FOREIGNPATENTS 931,182 9/ 1947 France. 591,474 1/ 1934 Germany.

OTHER REFERENCES Matthews: Application of Dyestuffs, New York,

published by John Wiley and Sons, Inc., 1920 T.P. 893 M3; page 191relied on.

IRVING BUNEVICH, Primary Examiner.

1. APPARATUS FOR CONTINUOUSLY AND UNFORMLY IMPREGNATING TUBULAR KNITFABRIC WITH A DYE LIQUID TO PROVIDE DYED TUBULAR KNITTED FABRIC FREE OFEDGE MARKS, WHICH COMPRISES (A) A RESERVOIR FOR MAINTAINING A BATH OFTHE LIQUID AT A PREDETERMINED LEVEL, (B) MEANS ADJACENT THE ENTRY END OFTHE RESERVOIR FOR GUIDING THE TUBULAR FABRIC AND PRESENTING IT IN FLATFORM INTO THE BATH, (C) A PLURALITY OF PRESSURE ROLLERS BELOW THESURFACE OF THE BATH AND FORMING A SUCCESSION OF SUBMERGED NIPS ARRANGEDSUCCESSIVELY TO RECEIVE AND APPLY CONCENTRATED PRESSURE TO THE FABRIC,(D) SAID PRESSURE ROLLERS BEING WHOLLY SUBMERGED IN SAID BATH, WHEREBYSAID FABRIC REMAINS CONTINUOUSLY AND WHOLLY SUBMERGED IN SAID BATH WHILEPASSING THROUGH SAID SUCCESSION OF SUBMERGED NIPS, (E) THE SUCCESSION OFSUBMERGED NIPS COMPRISING A PLURALITY OF NON-RESILIENT ROLLERS FORMINGCONCENTRATED PRESSURE NIPS, (F) CERTAIN OF THE NON-RESILIENT ROLLERSBEING MOUNTED FOR ROTATION ON NORMALLY FIXED AXES AND BEING SPACED FROMEACH OTHER, (G) THE REMAINDER OF THE NON-RESILIENT ROLLERS BEINGCONTROLLABLY AND FORCIBLY MOVABLE INTO AND OUT OF THE SPACES FORMEDBETWEEN THE FIXED ROLLERS, (H) THE MOVABLE ROLLERS BEING SUSPENDED ATEACH END BY PAIRS OF SUPPORT ARMS, (I) THE SUPPORT ARMS BEING PIVOTALLYSECURED TO YOKES AT OPPOSITE ENDS OF THE ROLLERS, (J) THE YOKES BEINGMOUNTED FOR PIVOTING MOVEMENT ABOUT AXES SUBSTANTIALLY CENTRALLY BETWEENTHE PIVOT AXES OF THE SUPPORT ARMS, (K) MEANS BEING PROVIDED FORCONTROLLABLY MOVING THE PIVOT AXES OF THE YOKES TOWARD AND AWAY FROM THENORMALLY FIXED ROLLERS, AND (1) AN EXTRACTING NIP MOUNTED ADJACENT THEEXIT END OF THE RESERVOIR AND ABOVE THE LEVEL OF THE BATH AND COMPRISINGA PAIR OF EXTRACTING ROLLS HAVING RESILIENT OUTER SURFACES, (M) SAIDPRESSURE ROLLERS BEING MOUNTED IN A CONTACTING SERIES, WHEREBY THEFABRIC IS CAUSED TO BE IN EDGE-TO-EDGE CONTROL CONTACT WITH ADIMENSIONALLY STABLE SURFACE WHILE PASSING THROUGH SAID SUBMERGED NIPS.